Pipe coupling having double-threaded tightening fastener and associated methods

ABSTRACT

A pipe coupling for coupling adjacent pipe ends of a pair of pipes includes a sleeve, a sealing gasket operatively coupled with the sleeve adjacent an open end of the sleeve, and a clamping element for compressing the sleeve or the sealing gasket into tightened engagement with one of the pipe ends. The clamping element includes two bolt flanges nominally spaced apart by a gap and a double threaded fastening bolt with two external threaded portions, which engage with two corresponding fastening nuts having right-hand thread and left-hand thread, respectively. Accordingly, when the fastening bolt is rotated, both the fastening nuts move towards or away from one another, thereby rapidly moving the bolt flanges to shrink the gap and compress the clamping element or to expand the gap. As such, less time and labor are required to operate the pipe coupling in the field.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a divisional of U.S. application Ser. No.14/827,424, filed Aug. 17, 2015, the disclosure of which is herebyincorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention relates to pipe couplings adapted to couple andseal adjacent pipe ends of two pipe sections of the same or differentdiameters, thereby to form a fluid communication joint between the pipeends.

BACKGROUND

Generally speaking, various types of conventional pipe couplings forcoupling and sealing adjacent pipe ends of two pipe sections include acoupling sleeve or collar with each pipe end extending into a respectiveend of the coupling sleeve. A gasket is held adjacent each end of thesleeve overlying the pipe section, or alternatively, along the length ofthe sleeve. To secure the pipe ends in place, at least one of the sleeveand the gasket(s) must be compressed onto the pipe ends to form atightened or sealing engagement. The various types of pipe couplingsavailable today include different types of clamping elements ormechanisms for producing this selective compression on the sleeve and/orthe gasket(s).

In one example, a pipe coupling is shown in U.S. Pat. No. 6,168,210 andutilizes continuous flanges (also referred to as “glands”) that arecoupled together via bolts spanning a longitudinal length of the sleeve.As described in that reference, the flanges, sleeve ends, and gasketshave particular relationships that affect the seal and allow thecoupling to work over a range of pipe sizes to compress the gasketsagainst the pipe ends as the flanges are drawn towards each other usingthe bolts.

In another example, a pipe coupling is shown in U.S. Pat. No. 8,528,945and utilizes split-ring glands that each encircle one of the sleeve endsand the gasket(s) adjacent that sleeve end. As described in thatreference, the encirclement of the sleeve end and the gasket(s) iscomplete except at a gap formed between spaced ends of two gland membersdefining the split-ring gland. Instead of requiring bolts that span thelongitudinal length of the sleeve, each split-ring gland can betightened independently by using a bolt to draw together bolt flangeslocated on the spaced ends of the split-ring gland. Once again, thegasket(s) and split-ring glands are designed to enable a wide range ofclamping force adjustment and gap size so as to engage with varioussizes of pipe ends at the sleeve.

Yet another example of a pipe coupling is commercially referred to as aStraub® pipe coupling, some of which are manufactured by Swiss companyStraub Werke AG and distributed by companies such as PerformanceCoupling Company of National City, Calif. As can be seen in productmanuals on their website straub-couplings.com, at least an outermostportion of the sleeve of this type of pipe coupling may be split todefine a gap that extends along the longitudinal length thereof. Thus,once the pipe ends are inserted into the opposing ends of the sleeve,this outermost portion or clamping elements secured to the outermostportion compress the gap by tightening a series of bolts extendingacross the gap between corresponding pairs of bolt flanges. Other typesof pipe couplings are also known, many of these being secured togetherand adjusted in compression with some type of threaded fastener and boltarrangement, just as in the three specific examples described above.

Consequently, many of the pipe couplings used in the field today areinstalled and adjusted using threaded bolts and nuts. Typically, asocket wrench or some sort of similar tool must be used to rotate thebolts to perform the installation process. However, many pipe couplingsare provided with a wide range of adjustable compression that may beapplied, and so the bolts may need to be moved a significant length ordistance during the tightening of the pipe coupling onto the pipe ends.In addition to requiring more time and manual labor for longermovements, specialty socket wrenches must sometimes be provided tohandle the long length of movement from the starting or nominal(uncompressed) position to the fully compressed and sealed engagementposition. The added complexity of parts and tools for the job may beundesirable when working in the field, such as when an installer isworking in dark or poor environmental conditions on a buried pipeconnection.

As such, it would be desirable to further improve the various types ofconventional pipe couplings to minimize the number of separate or looseparts and tools that an installer must work with when connecting twopipe ends using the pipe coupling. Furthermore, it would also bedesirable to reduce the time and manual labor required to install thesepipe couplings, thereby making the users more efficient overall.

SUMMARY

In accordance with one embodiment of the invention, a pipe coupling isprovided for sealingly coupling two pipe ends together. The pipecoupling includes a sleeve, a sealing gasket operatively coupled withthe sleeve, and a clamping element operatively coupled with the sleeve.The sleeve has a generally cylindrical body portion with open opposingends that receive the two pipe ends, and the sealing gasket engages atleast one of the two pipe ends. The clamping element is used to compressthe sealing gasket into tightened engagement with at least one of thetwo pipe ends. For example, if each clamping element produces tightenedengagement with only one of the pipe ends, a second clamping elementwill be provided to produce tightened engagement with the other of thepipe ends, thereby completing a sealed joint with fluid communicationbetween the two pipe ends. The clamping element includes first andsecond bolt flanges which are nominally spaced from one another todefine a gap between them, a double threaded fastening bolt extendinggenerally tangential to the generally cylindrical body portion andthrough the bolt flanges, and first and second fastening nuts inthreaded engagement with the fastening bolt. More specifically, thefastening bolt includes first and second external threaded portionsconnected at a central bolt portion, and these external threadedportions and the fastening nuts define corresponding right-hand threadand left-hand thread. Thus, as the fastening bolt is rotated, bothfastening nuts move along the external threaded portions towards or awayfrom one another and the central bolt portion, thereby reducing thelabor and time required for installing the pipe coupling.

In one aspect of this embodiment, at least one of the bolt flanges andthe fastening nuts include corresponding features that prevent rotationof the fastening nuts relative to the bolt flanges when the fasteningnuts are in abutting engagement with the bolt flanges. In one example,each of the bolt flanges defines a socket with an arcuate surface, andeach of the fastening nuts includes an arcuate surface that ispositioned in face-to-face contact with the arcuate surface within thesocket. This face-to-face contact of the arcuate surfaces preventsrotation of the fastening nuts relative to the bolt flanges. As such,rotation of the fastening bolt causes lengthwise movement of thefastening nuts and the bolt flanges along the fastening bolt. Thefastening nuts are swivel nuts with a semicircular prism shape andthreaded bores, in this example.

In another aspect, consistent with this embodiment of the pipe coupling,the clamping element includes no washers used in conjunction with thebolt flanges and the fastening nuts. In this regard, the clampingelement consists only of two fastening nuts, the fastening bolt, and theelements carrying the first and second bolt flanges. Accordingly, areduced or minimized number of parts needs need to be accounted for andworked with when installing the pipe coupling onto the pipe ends.

To enable assembly of the clamping element as described above, thefastening bolt may further include a removable head portion that iscoupled with one of the first and second external threaded portions. Theremovable head portion is secured in position on this external threadedportion after the fastening bolt is engaged with the same externalthreaded portion, which thereafter enables the fastening bolt to beengaged by a driver such as a socket wrench for rotating the bolt. Theremovable head portion may be in threaded engagement with the externalthreaded portion, in one example, although it will be understood thatsome additional form of positive lock or securing may also be requiredto prevent the head portion from simply rotating off the remainder ofthe fastening bolt when the pipe coupling is in use, particularly whenthe fastening bolt is configured to be re-used.

The first and second fastening nuts, in some embodiments, define anouter peripheral surface and chamfered openings at an intersection ofthe outer peripheral surface and the threaded bores extending throughthe fastening nuts. The chamfered openings help guide the fastening boltinto the threaded engagement with the threaded bore, which isparticularly useful when an installer does not have good visibility wheninstalling or adjusting the pipe coupling in the field. The fasteningnuts and the fastening bolt are typically formed from stainless steelfor providing the desired amount of strength, cost-efficiency, anddurability under the loads typically placed on the pipe coupling.

This embodiment of the pipe coupling may be used with several types ofspecific clamping elements. In one example, the clamping elementincludes a U-shaped gland that engages and at least partially surroundsa flange on one open opposing end of the sleeve and an adjacent sealinggasket as well. The U-shaped gland therefore surrounds one of the twopipe ends also. The gland includes spaced ends including the first andsecond bolt flanges, such that the spaced ends can be drawn together tocompress the gland and the annular gasket onto the pipe end. TheU-shaped gland may more particularly include a split-ring gland with twopartially circular gland members defining abutting ends at one side andthe spaced ends on the other side. An armor may be inserted to span thegap between the spaced ends, thereby forming a generally closed annularperiphery with the gland members for the sealing gasket. In anotherexample, the clamping element includes first and second elongated boltflange members secured with the sleeve and defining the first and secondbolt flanges, respectively. The first and second bolt flanges in thisexample include a plurality of bores aligned along a longitudinal lengthof the sleeve, such that a plurality of double threaded fastening boltsare received in these bores. The fastening bolts are tightened tocompress the sleeve at multiple locations onto the pipe ends. The sleeveof this example may include an elongated split-ring cylinder with spacedends carrying the first and second elongated bolt flange members, suchthat tightening of the fastening bolts shrinks the gap of the split-ringcylinder. Regardless of the clamping element used with the pipecoupling, the time and manual labor required to install the pipecoupling is significantly reduced by using the double threaded fasteningbolts as described above.

The operation of the pipe coupling described above defines a method ofconnecting pipe ends together, in accordance with another embodiment ofthe invention. The method includes positioning the sealing gasketadjacent one of the open opposing ends of the sleeve and inserting apipe end into the open opposing end of the sleeve such that the sealinggasket and a portion of the sleeve surround the pipe end. The clampingelement is engaged with the open opposing end of the sleeve and thesealing gasket such that the clamping element is operatively coupledwith the sleeve. First and second bolt flanges on the clamping elementare nominally spaced from one another by a gap when these elements areoperatively coupled as described. The fastening bolt is inserted toextend through the first and second bolt flanges, with the first andsecond fastening nuts threadably engaged with the first and secondexternal threaded portions of the fastening bolt. The fastening nuts arespecifically positioned to abut the corresponding first and second boltflanges. The method then includes rotating the fastening bolt in a firstdirection to cause the first and second fastening nuts to move along theexternal threaded portions towards one another, thereby drawing the boltflanges towards one another to shrink the gap therebetween and compressthe sealing gasket and the sleeve into tighter engagement with the pipeend. The rotation of the fastening bolt advantageously results in twiceas much movement of the bolt flanges towards one another compared tofastening bolts engaged with only a single fastening nut.

When the pipe end is later to be removed from the pipe coupling, themethod further includes rotating the fastening bolt in a seconddirection opposite the first direction. This rotation in the seconddirection causes the first and second fastening nuts to move along theexternal threaded portions away from one another, thereby allowing thebolt flanges to move away from one another and expand the gaptherebetween. This movement releases the compressive engagement of thesealing gasket and the sleeve with the pipe end. The pipe end is thenwithdrawn from the open opposing end of the sleeve and from the clampingelement.

In one aspect, the bolt flanges and/or the fastening nuts includecorresponding features configured to prevent relative rotation. When thefastening nuts are moved into abutting engagement with the bolt flanges,these corresponding features are engaged. Thus, the method also includespreventing relative rotation of the fastening nuts and the bolt flangeswith the corresponding features during rotation of the fastening bolt.In a further example, engaging the corresponding features includesinserting the fastening nuts into sockets provided in the bolt flanges.The fastening nuts and the sockets in the bolt flanges further includearcuate surfaces that are brought into face-to-face contact to definethe abutting engagement in some embodiments.

In another aspect, a removable head portion is threadably engaged withthe fastening bolt after the fastening bolt is inserted to extendthrough the bolt flanges with the fastening nuts in position. Theremovable head portion is configured to engage with a driver such as asocket wrench when rotating the fastening bolt.

One alternative type of embodiment of a pipe coupling for sealinglycoupling two pipe ends together is also provided. The pipe coupling ofthis embodiment again includes a sleeve with open opposing ends, asealing gasket, and a clamping element. The clamping element is modifiedto include first and second clamp members operatively coupled with theopen opposing ends of the sleeve and the sealing gasket. The first andsecond clamp members include respective first and second bolt flanges.The double threaded fastening bolt is again used, but this time thefastening bolt extends generally parallel to a longitudinal length ofthe cylindrical body portion of the sleeve to also extend through thefirst and second bolt flanges. The clamping element again includes firstand second fastening nuts with right-hand thread and left-hand threadconfigured to engage with corresponding external threaded portions onthe fastening bolt. When the fastening bolt of this embodiment isrotated, the first and second bolt flanges and the first and secondclamp members are drawn towards one another, which causes compression ofthe sealing gasket and/or the sleeve to create a tightened engagementwith the pipe ends. Also like the previously described embodiment, thebolt flanges and clamp members favorably move towards or away from oneanother twice as fast (or with half as much bolt rotation) asconventional designs.

The various features of the embodiments described above may be combinedin any configuration as desired. Various additional features andadvantages of the invention will become more apparent upon review of thefollowing detailed description of the illustrative embodiments taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a first embodiment of a pipe couplingutilizing a clamping element with a double threaded fastening bolt, inaccordance with the principles of the described invention, and in afully assembled state.

FIG. 2 is a perspective view of the pipe coupling of FIG. 1, with pipeends of two pipes added in the illustration for purposes of describingthe use of the pipe coupling to couple the two pipes in fluidcommunication and sealed engagement.

FIG. 3 is a partially-exploded perspective view of the pipe coupling ofFIG. 1, illustrating the various components of a clamping element usedwith this embodiment.

FIG. 4 is a longitudinal cross-sectional view of one end of the pipecoupling of FIG. 1, taken specifically along line 4-4 in FIG. 1 to showthe engagement of the pipe coupling with one of the pipe ends.

FIG. 5 is a lateral cross-sectional view of one end of the pipe couplingof FIG. 1, taken specifically along line 5-5 in FIG. 1 to show thefeatures of the clamping element, including the fastening bolt, twofastening nuts, and two bolt flanges.

FIG. 6 is an end view of the pipe coupling of FIG. 1 in a first state,wherein the bolt flanges of the clamping element are spaced by a nominalgap and the pipe coupling is not in tightened engagement with the pipeend.

FIG. 7 is an end view of the pipe coupling like FIG. 6 but in a secondstate, wherein the bolt flanges of the clamping element are drawntogether to shrink the gap, which causes the pipe coupling to be intightened engagement with the pipe end.

FIG. 8 is a perspective view of a second embodiment of a pipe couplingutilizing a clamping element with a plurality of double threadedfastening bolts, in accordance with the principles of the describedinvention, and in a fully assembled state.

FIG. 9 is a perspective view of a third embodiment of a pipe couplingutilizing a clamping element with a double threaded fastening bolt, inaccordance with the principles of the described invention, and in afully assembled state, with the double threaded fastening bolt extendingalong the longitudinal length of a sleeve of the pipe coupling.

FIG. 10 is a longitudinal cross-sectional view of one end of the pipecoupling of FIG. 9, taken specifically along line 10-10 in FIG. 9 toshow the engagement of the pipe coupling with one of the pipe ends.

FIG. 10A is a longitudinal cross-sectional view of one end of analternative version of a pipe coupling that is similar to the one shownin FIGS. 9 and 10, but with further features of an alternative versionof the fastening nuts and the bolt flanges shown in more detail.

DETAILED DESCRIPTION

In FIGS. 1 through 7, a pipe coupling 10 according to one embodiment ofthe present invention is shown. The pipe coupling 10 of this embodimentis typically referred to as a split-ring gland type of pipe coupling.With reference to FIGS. 1 through 3, the pipe coupling 10 includes asleeve 12, a pair of split-ring glands 14 (defining a substantiallyU-shaped gland), an armor 16 associated with each split-ring gland 14,and an annular sealing gasket 18 associated with each split-ring gland14. More specifically, the sleeve 12 includes a generally cylindricalbody portion 20 with opposing open ends 22, with each of the open ends22 being operatively coupled with one of the split-ring glands 14, onearmor 16, and one annular sealing gasket 18. As a result, in the fullyassembled state of the pipe coupling 10, a pipe end E1 of a first pipeP1 is inserted into the sleeve 12 through one of the split-ring glands14 and the corresponding sealing gasket 18, and a pipe end E2 of asecond pipe P2 is inserted into the other split-ring gland 14 andassociated gasket 18. Each of the split-ring glands 14 defines part of aclamping element 24 which is used to compress the corresponding sealinggasket 18 into a tightened sealed engagement with the corresponding pipeend E1, E2. Advantageously, the clamping element 24 of this embodimentuses a double threaded fastening bolt 26 engaged with first and secondfastening nuts 28, 30 to simplify the assembly of parts needed to formthe tightened engagement of the pipe coupling 10 on the first and secondpipes P1, P2. In this regard, and as described below, the clampingelement 24 enables connection of the pipes P1, P2 with the pipe couplingusing less time and manual labor than conventional pipe couplingdesigns. Various aspects have been omitted for improved clarity, theseaspects are fully shown and described in U.S. Pat. Nos. 6,168,210 and8,528,945, both of which are incorporated herein by reference.

In the fully assembled state of the pipe coupling 10, the split-ringglands 14 are configured to be tightened onto the corresponding sealinggaskets 18 to compress the sealing gaskets 18 into sealing connectionwith the respective pipe ends E1, E2. The split-ring gland 14 and thearmor 16 collectively define a generally closed annular periphery 32around the sealing gasket 18, which further ensures that fluid passingthrough the pipes P1, P2 and the pipe coupling 10 does not leak past thesealing gasket 18 and out of the pipe coupling 10. Thus, the pipecoupling 10 provides a sealed coupling of two adjacent pipe ends E1, E2in fluid communication.

Further details of the components of the pipe coupling 10 are shown inFIG. 3, in which one of the split-ring glands 14 is shown partiallyexploded to facilitate discussion. The generally cylindrical bodyportion 20 of sleeve 12 defines a longitudinal axis LA of the pipecoupling 10. At each of the opposing ends 22, the sleeve 12 furtherincludes a radially outwardly-directed flange 34 that is used toaccurately locate the split-ring gland 14 and the annular sealing gasket18, as described in further detail below. Although the sleeve 12 of theexemplary embodiment is shown as cylindrical, it will be understood thatthe body portion 20 of the sleeve 12 may also be tapered slightlyinwardly adjacent both open ends 22 to provide clearance for slightangles between the pipe ends E1, E2 to be coupled in fluid communicationby the pipe coupling 10.

Each of the split-ring glands 14 shown in FIGS. 1 through 3 includes afirst partially-circular gland member 36 a and a secondpartially-circular gland member 36 b. The gland members 36 a, 36 b eachdefine a half-moon shape and are configured to be centered about thelongitudinal axis LA of the pipe coupling 10. The gland members 36 a, 36b define respective abutting ends 38 a, 38 b at one side and respectivespaced ends 40 a, 40 b on the other side, each of which is discussed inturn below.

The abutting ends 38 a, 38 b are configured to be securely coupledtogether in generally gap-free relationship as shown in FIGS. 1 and 2.To this end, the abutting end 38 a of the first gland member 36 aincludes a first abutting bolt flange 42 a projecting radially outwardlyfrom the abutting end 38 a. Similarly, the abutting end 38 b of thesecond gland member 36 b includes a second abutting bolt flange 42 bprojecting radially outwardly from the abutting end 38 b.

The first and second abutting bolt flanges 42 a, 42 b includecorresponding apertures 44 a, 44 b (shown in FIG. 3) oriented tangentialto the axis LA and configured to receive a fastener, for example, thethreaded bolt 46. The bolt 46 extends through the apertures 44 a, 44 b,such that the bolt 46 is also oriented generally tangential to thesplit-ring gland 14 in the illustrated embodiment of the pipe coupling10. Each of the apertures 44 a, 44 b is threaded in the illustratedembodiment for engaging with threads on the bolt 46, but it will beunderstood that these apertures 44 a, 44 b may be modified in otherembodiments so that only one (e.g., a threaded bore only at 44 b) ornone of these includes threading (in which case, a nut would be used totighten the bolt 46 in position within the apertures 44 a, 44 b).Consequently, when the bolt 46 securely couples the abutting ends 38 a,38 b, the gland members 36 a, 36 b are restrained from pivotallyrotating relative to each other, such that the ends 40 a, 40 b arerestrained from scissoring apart. The first and second abutting boltflanges 42 a, 42 b may be provided with opposing countersinks 50 a, 50 b(only 50 a is shown in FIG. 3) facing away from one another andconfigured to receive the head 46 a of the bolt 46 generally flush withthe structure of the first and second abutting bolt flanges 42 a, 42 b.However, the first and second abutting bolt flanges 42 a, 42 b may besecurely coupled by alternative fasteners as alluded to above.

Now considering the spaced ends 40 a, 40 b, the first and second glandmembers 36 a, 36 b respectively include first and second spaced boltflanges 52 a, 52 b. The first and second spaced bolt flanges 52 a, 52 bproject radially outwardly from the spaced ends 40 a, 40 b of the firstand second gland members 36 a, 36 b. The spaced bolt flanges 52 a, 52 binclude corresponding apertures 54 a, 54 b (only 54 b is shown in FIG.2) configured to receive the double threaded fastening bolt 26therethrough. Each of the spaced bolt flanges 52 a, 52 b may define asocket with a convex arcuate surface 56 a, 56 b between the spaced ends40 a, 40 b and a concave arcuate surface 58 a, 58 b (shown in FIG. 5).The first and second fastening nuts 28, 30 include convex arcuatesurfaces 60 a, 60 b configured to be received by the concave arcuatesurfaces 58 a, 58 b of the first and second spaced bolt flanges 52 a, 52b.

As shown in FIG. 3, the first and second fastening nuts 28, 30 areswivel nuts with a semicircular prism shape and threaded bores, however,other fastening nuts 28, 30 may also be suitable. As shown in FIG. 5,the convex arcuate surfaces 60 a, 60 b of the first and second fasteningnuts 28, 30 enable face-to-face contact with the concave arcuatesurfaces 58 a, 58 b of the first and second spaced bolt flanges 52 a, 52b within the socket. This face-to-face contact of the arcuate surfacesprevents rotation of the first and second fastening nuts 28, 30 relativeto the first and second spaced bolt flanges 52 a, 52 b. The convexarcuate surfaces 60 a, 60 b of fastening nuts 28, 30 provide onesuitable example of corresponding features that prevent rotation of thefirst and second fastening nuts 28, 30 relative to the first and secondspaced bolt flanges 52 a, 52 b when the first and second fastening nuts28, 30 are in abutting engagement with the first and second spaced boltflanges 52 a, 52 b.

A double threaded fastening bolt 26 extends generally tangential to thegenerally cylindrical body portion 20 of sleeve 12 and extends throughfirst and second spaced bolt flanges 52 a, 52 b, and into at least aportion of the first and second fastening nuts 28, 30 as shown in FIG.5. The double threaded fastening bolt 26 includes first and secondexternal threaded portions 62, 64 connected at a central bolt portion66. As shown, the first external threaded portion 62 and the firstfastening nuts 28 are both right-hand threaded, while the secondexternal threaded portion 64 and the second fastening nut 30 are bothleft-hand threaded. Rotation of the double threaded fastening bolt 26causes lengthwise movement of the first and second fastening nuts 28, 30and the first and second spaced bolt flanges 52 a, 52 b along the doublethreaded fastening bolt 26. In other words, when the first and secondfastening nuts 28, 30 are in abutting engagement with first and secondspaced bolt flanges 52 a, 52 b, this movement also causes movement offirst and second spaced bolt flanges 52 a, 52 b towards one another tocompress the sleeve 12 and/or the sealing gasket 18. Specifically, asthe double threaded fastening bolt 26 is rotated for tightening of thefirst and second spaced bolt flanges 52 a, 52 b, the first fastening nut28 moves along the first external threaded portion 62 towards thecentral bolt portion 66, while the second fastening nut 30 moves alongthe second external threaded portion 64 towards the central bolt portion66. This serves to tighten the clamping element 24, thus sealing thepipe coupling 10 to the first and second ends E1, E2 of the respectivefirst and second pipes P1, P2. Conversely, to loosen the clampingelement 24 of the pipe coupling 10, the first and second fastening nuts28, 30 are moved away from each other on first and second externalthreaded portions 62, 64.

FIGS. 6 and 7 show the coupling 10 moving between a first state wherethe clamping element 24 has not yet been tightened and a second state,where the clamping element 24 has been tightened to draw the spaced boltflanges 52 a, 52 b and the spaced ends 40 a, 40 b closer together, tothereby compress the annular sealing gasket 18. In FIGS. 6 and 7, thegap is defined by the distance between the spaced bolt flanges 52 a, 52b. In FIG. 6, when the pipe coupling 10 is in a first state, the firstand second spaced bolt flanges 52 a, 52 b of the clamping element 24 arespaced apart by a gap having a first width W1. As shown in FIG. 7, whenthe pipe coupling is tightened to a second state, the first and secondspaced bolt flanges 52 a, 52 b of the clamping element 24 are drawntogether to shrink the gap to a second width W2. Since the first andsecond external threaded portions 62, 64 of the double threadedfastening bolt draw both the first and second spaced bolt flanges 52 a,52 b together simultaneously, the double threaded fastening bolt 26 onlyneeds to rotate half as much as a conventional fastening bolt with asingle nut to achieve the same level of adjustment of clamping element24. Thus, the labor and time required are reduced for installing thepipe coupling 10. Further, normal socket wrench tools can beadvantageously used during the installation and assembly.

In order to enable assembly of the clamping element 24 as describedabove, the double threaded fastening bolt 26 may include a removablehead portion 68 that is coupled with one of the first and secondexternal threaded portions 62, 64. The removable head portion 68 may besecured in a suitable position on the external threaded portion 62, 64after the double threaded fastening bolt 26 is inserted through thefirst and second spaced bolt flanges 52 a, 52 b with the fastening nuts28, 30 in position. As shown in FIG. 5, the removable head portion 68may be threadably engaged with the double threaded fastening bolt 26.Alternatively, or in addition to being threadably engaged with thedouble threaded fastening bolt 26, a locking mechanism (not shown) maybe provided to prevent the removable head portion 68 from loosening orcompletely rotating off the double threaded fastening bolt 26.

The first and second fastening nuts 28, 30, may define an outerperipheral surface and chamfered openings at an intersection of theouter peripheral surface and the threaded bores extending through thefastening nuts. The chamfered openings help to guide the fastening boltinto the threaded engagement with the threaded bore, which isparticularly useful when an installer does not have good visibility wheninstalling or adjusting the pipe coupling in the field. The first andsecond fastening nuts 28, 30 and the double threaded fastening bolt 26will be formed from any suitable material. One such suitable material isstainless steel that provides the desired amount of strength,cost-efficiency, and durability under the loads typically placed on thepipe coupling 10.

The clamping element 24 does not require the use of washers incombination with the first and second abutting bolt flanges 42 a, 42 b,the first and second spaced bolt flanges 52 a, 52 b and the first andsecond fastening nuts 28, 30. In this regard, the clamping element 24may consist of simply first and second fastening nuts 28, 30, doublethreaded fastening bolts 26, and the elements carrying the first andsecond spaced bolt flanges 52 a, 52 b.

The first and second gland members 36 a, 36 b each include apartially-cylindrical annular wall 70 with an inner edge 72 and an outeredge 74. The partially-cylindrical annular walls 70 are generally flatrather than concave in cross section. The first and second gland members36 a, 36 b each further include an inwardly-directed U-shaped wall 76 atthe inner edge 72 of the annular wall 70. The U-shaped walls 76 areconfigured to receive the flange 34 at the end 22 of the sleeve 12,thereby accurately locating the split-ring gland 14 on the sleeve 12.

The first and second gland members 36 a, 36 b each also include an outerwall 78 extending inwardly in a radial direction at the outer edge 74.As described in further detail below, at least a portion of the annularsealing gasket 18 is captured between the outer walls 78 and the flange34 of the sleeve 12. Thus, the annular walls 70, the outer walls 78, andthe flange 34 of the sleeve 12 collectively define a gasket seat 80(shown in FIG. 4) for the split-ring gland 14. In the exemplaryembodiment shown, the split-ring gland 14 may be tightened between aminimum diameter of about 10.00 inches±0.13 inch and a maximum diameterof about 10.81 inches±0.25 inch. The sleeve 12 and the split-ring gland14 are each formed from carbon steel in one embodiment, but thesecomponents may alternatively be formed from stainless steel, plastic, oranother suitable structural material.

The armor 16 is more clearly shown in FIGS. 3 and 4. The armor 16 may beinserted to span the gap between the spaced ends 40 a, 40 b, therebyforming a generally closed annular periphery with first and second glandmembers 36 a, 36 b for the annular sealing gasket 18. The armor 16 isgenerally S-shaped in cross section and has an arcuate shape along itslength. The armor 16 includes a central wall 82 with an inner side edge84 and an outer side edge 86. The armor 16 also includes an inner sidewall 88 extending generally perpendicular to, and radially inwardly of,the central wall 82 at the inner side edge 84, and an outer side wall 90extending generally perpendicular to, and radially outwardly of, thecentral wall 82 at the outer side edge 86. The inner side wall 88 andthe outer side wall 90 extend in differing directions from the centralwall 82 to form the generally S-shaped cross section of the armor 16.The central wall 82 further includes lateral side edges 92 extendingfrom the inner side edge 84 to the outer side edge 86.

When the armor 16 is positioned at the gap between the spaced ends 40 a,40 b of the gland members 36 a, 36 b, the central wall 82 is positionedadjacent the annular walls 70 of the gland members 36 a, 36 b at thespaced ends 40 a, 40 b. To this end, the central wall 82 of the armor 16defines an arc length that is at least long enough to span the gap suchthat the lateral side edges 92 of the central wall 82 are disposedunderneath the annular walls 70 of the gland members 36 a, 36 b in thenominal position of the split-ring gland 14. In this position, the innerside wall 88 projects into the U-shaped walls 76 of the gland members 36a, 36 b, and the outer side wall 90 is positioned adjacent the outerwalls 78 of the gland members 36 a, 36 b at the spaced ends 40 a, 40 b.Thus, the armor 16 and the split-ring gland 14 collectively define aclosed ring or loop for receiving the annular sealing gasket 18. Morespecifically, the central wall 82 of the armor 16 cooperates with theannular walls 70 of the gland members 36 a, 36 b to collectively definethe generally closed annular periphery 32 for the annular sealing gasket18. In the exemplary embodiment, the armor 16 is configured to cover atleast about 15% to about 30%, and advantageously, about 20% of thecircumference of the sealing gasket 18 when the sealing gasket 18 isinstalled in the split-ring gland 14.

To assemble the pipe coupling, two split-ring glands 14 are assembledwith the armors 16 and the gaskets 18 on the opposing open ends 22 ofthe sleeve 12. For each of the split-ring glands 14, the two glandmembers 36 a, 36 b are brought together such that the U-shaped wall 76of the split-ring gland 14 is engaged or seated onto the radiallydirected outward flange 34 at one open end 22 of the sleeve 12. Thefirst and second abutting ends 38 a, 38 b of the first and second glandmembers 36 a, 36 b are securely coupled in a gap free relationship withthe bolt 46. Securely coupling the first and second abutting ends 38 a,38 b in this manner will provide a gap having a first width W1 betweenthe first and second spaced ends 40 a, 40 b. The bolt 46 is orientedtangential to the gland members 36 a, 36 b and therefore restrains thegland members 36 a, 36 b from scissoring outwardly at the spaced ends 40a, 40 b and increasing the length of the gap from the nominal W1. Thearmor 16 is inserted to span the gap between the spaced ends 40 a, 40 bof the gland members 36 a, 36 b and to form a generally closed annularperiphery 32 with the gland members 36 a, 36 b. The annular sealinggasket 18 is inserted into the closed annular periphery 32 of the armor16 and the first and second gland members 36 a, 36 b. Alternatively, thearmor 16 may be sitting on the sealing gasket 18 and the first andsecond gland members 36 a, 36 b may be brought together over the flange34, the armor 16, and the sealing gasket 18 simultaneously.

The spaced ends 40 a, 40 b may be coupled by the double threadedfastening bolt 26 and first and second nuts 28, 30. The double threadedfastening bolt 26 and first and second nuts 28, 30 may be looselyengaged to leave the gap at a first width W1, or, alternatively, may betightened to begin compressing the gasket 18 to leave a gap of a secondwidth W2. The pipe coupling 10 may be packed and shipped in thisassembled state in one embodiment. Alternatively, each of the split-ringglands 14 may be assembled with the corresponding armor 16 and sealinggasket 18 as described above without seating the U-shaped wall 76 of thesplit-ring gland 14 onto the flange 34 of the sleeve 12. In thisassembly, the split-ring glands 14 may be shipped separately from thesleeve 12 and may be assembled with the sleeve 12 at a jobsite. Thesplit-ring glands 14 will need to be loosened and mounted on thecorresponding flanges 34 of the sleeve 12 at the jobsite in theseembodiments. Any of the above-described assembly steps may be undone andrepeated as required during installation and/or removal of the pipecoupling 10.

The method includes positioning the sealing gasket 18 adjacent one ofthe open opposing ends 22 of the sleeve 12 and inserting a pipe end E1,E2 into the open opposing end 22 of the sleeve 12 such that the sealinggasket 18 and a portion of the sleeve 12 surround the pipe end E1, E2.Specifically, with reference to FIG. 2, the pipe end E1 of the firstpipe P1 is inserted through the gasket opening 94 of a first split-ringgland 14 and through one open end 22 into the sleeve 12 (arrow 96). Thepipe end E2 of the second pipe P2 is inserted through the gasket opening94 of a second split-ring gland 14 and through the other open end 22into the sleeve 12 (arrow 98). The clamping element 24 is engaged withthe open opposing end 22 of the sleeve 12 and the sealing gasket 18 suchthat the clamping element 24 is operatively coupled with the sleeve 12.First and second spaced bolt flanges 52 a, 52 b on the clamping element24 are nominally spaced from one another by a gap of a first width W1when these elements are operatively coupled. The double threadedfastening bolt 26 is inserted to extend through the first and secondspaced bolt flanges 52 a, 52 b, with the first and second fastening nuts28, 30 threadably engaged with the first and second external threadedportions 62, 64 of the double threaded fastening bolt 26. The first andsecond fastening nuts 28, 30 are specifically positioned to abut thecorresponding first and second spaced bolt flanges 52 a, 52 b.

The fastening bolt is then rotated in a first direction to cause thefirst and second fastening nuts 28, 30 to move along the first andsecond external threaded portions 62, 64 towards one another, therebydrawing the first and second spaced bolt flanges 52 a, 52 b towards oneanother to shrink the gap therebetween and compress the sealing gasket18 and the sleeve 12 into tighter engagement with the corresponding pipeend E1, E2. As the double threaded fastening bolt 26 is tightened, thegap is shortened from a first width W1 to a second width W2 (as shown inFIGS. 6 and 7) between the first and second spaced ends 40 a, 40 bthereof (arrow 100) and thereby generally uniformly compress thecorresponding annular sealing gasket 18 into sealed engagement with thefirst pipe P1. The double threaded fastening bolt 26 and first andsecond nuts 28, 30 of the second split-ring gland 14 are tightened toshorten the gap to a second width W2 between the spaced ends 40 a, 40 bthereof (arrow 102) and thereby generally uniformly compress thecorresponding annular sealing gasket 18 into sealed engagement with thesecond pipe P2. Each pipe P1, P2 may be inserted into the sleeve 12prior to tightening the split-ring glands 14, or one pipe (e.g., P1) maybe inserted and tightened into position before the other pipe (e.g., P2)is inserted and tightened into position. The rotation of the doublethreaded fastening bolt 26 advantageously results in twice as muchmovement of the bolt flanges towards one another compared to fasteningbolts engaged with only a single fastening nut.

When the pipe end E1, E2 is later to be removed from the pipe coupling10, the method includes rotating the double threaded fastening bolt 26in a second direction opposite the first direction. This rotation in thesecond direction causes the first and second fastening nuts 28, 30 tomove along the external threaded portions 62, 64 away from one another,thereby allowing the first and second spaced bolt flanges 52 a, 52 b tomove away from one another and expand the gap, possibly from the secondwidth W2 to the first width W1, therebetween. This movement releases thecompressive engagement of the sealing gasket 18 and the sleeve 12 withthe pipe end E1, E2. The pipe end E1, E2 is then withdrawn from the openopposing end 22 of the sleeve 12 and from the clamping element 24.

FIG. 8 illustrates another embodiment of a pipe coupling 110 forsealingly coupling two pipe ends E1, E2 (not shown) together accordingto the principles of the present invention. It will be understood thatmany of the components of this pipe coupling 110 are similar to thosedescribed above with reference to the first embodiment. This embodimentoperates in much the same manner as the first embodiment. Accordingly,the same reference numbers have been used on identical elementsappearing in the drawings without further description herein. The pipecoupling 110 of this embodiment is typically referred to as a Straub®pipe coupling. In this embodiment, sleeve 112 includes a body portion120 that extends along the longitudinal axis LA of the pipe coupling110. The sleeve 112 has a plurality of spaced slots 104 parallel to thelongitudinal axis LA. The first and second spaced bolt flanges 152 a,152 b include a plurality of bores 106 aligned along a longitudinallength of the sleeve 112 and drilled generally perpendicular to thelongitudinal axis LA, such that a plurality of double threaded fasteningbolts 26 is received through spaced slots 104 and into the bores 106, todefine a clamping element 124.

As shown in FIG. 8, the first and second spaced bolt flanges 152 a, 152b include two parallel rods spaced at a distance from each other. Inthis embodiment, the first and second spaced bolt flanges 152 a, 152 bare inserted generally parallel to the longitudinal axis LA, and includea plurality of bores 106. As previously discussed, the double threadedfastening bolt 26 includes first and second external threaded portions62, 64 connected at a central bolt portion 66. As shown in FIG. 8, threedouble threaded fastening bolts 26 extend generally tangential to thebody portion 120 of sleeve 112. The three double threaded fasteningbolts 26 extend through the three bores 106 of the first and secondspaced bolt flanges 152 a, 152 b. Further, the three double threadedfastening bolts 26 are secured by three fastening nuts 28. As the doublethreaded fastening bolt 26 is tightened, the first and second spacedbolt flanges 152 a, 152 b move closer to one another as previouslydescribed. While three double threaded fastening bolts 26 are shown withthree sets of slots 104 and three bores 106 in each of the first andsecond spaced bolt flanges 152 a, 152 b, more or fewer double threadedfastening bolts 26 and accompanying slots 104 and bores 106 may bedesired.

FIGS. 9 and 10 illustrate another embodiment of a pipe coupling forsealingly coupling two pipe ends E1, E2 together according to theprinciples of the present invention, where multiple double threadedfastening bolts 26 extend along the longitudinal length of a sleeve 212of the pipe coupling 210. This embodiment operates in a similar manneras the previous embodiments. The clamping element 224 includes first andsecond clamp members 108 a, 108 b operatively coupled with the openopposing ends 222 of the sleeve 212 and the sealing gasket 218. Thefirst and second clamp members 108 a, 108 b include respective first andsecond spaced bolt flanges 252 a, 252 b. Double threaded fastening bolts26 (four shown in FIG. 9 and three shown in FIG. 10) extend generallyparallel to the longitudinal length of the cylindrical body portion 220of the sleeve 212 so as to also extend through the first and secondspaced bolt flanges 252 a, 252 b. The clamping element 224 againincludes first and second fastening nuts 28, 30 with right-handedthreads and left-handed threads to engage with the corresponding firstand second external threaded portions 62, 64 on the double threadedfastening bolt 26. When the double threaded fastening bolts 26 arerotated, and the first and second clamp members 108 a, 108 b includingthe first and second spaced bolt flanges 252 a, 252 b are drawn towardsone another, causing the compression of the sealing gasket 218 and/orthe sleeve 212. This creates a tightened engagement with the pipe endsE1, E2, as a result of the wedge-shaped configuration of gaskets 218 andsleeve ends 222. To this end, the wedge shape causes inward compressionof gaskets 218 into sealed engagement with pipe ends E1, E2 when thefastening bolts 26 are tightened to draw the gaskets 218 longitudinallyinwardly towards the sleeve ends 222. Using double threaded fasteningbolts 26 advantageously enables the first and second spaced bolt flanges252 a, 252 b and first and second clamp members 108 a, 108 b to movetowards or away from one another twice as fast (or with half as muchbolt rotation) as conventional designs. A similar design of this styleof pipe coupling where the fastening nuts 28, 30 and the bolt flanges252 a, 252 b are formed with convex arcuate surfaces (consistent withthe previous embodiment shown in FIG. 5 and described in detail above)is shown in FIG. 10A.

By virtue of the foregoing, there is thus provided an improved pipecoupling in accordance with various aspects of the present invention.While the present invention has been illustrated by the description ofembodiments thereof, and while the embodiments have been described inconsiderable detail, it is not intended to restrict or in any way limitthe scope of the appended claims to such detail. Additional advantagesand modifications will readily appear to those skilled in the art.Further, while shown as being used to couple two pipe ends E1, E2 viathe sleeve 12, only one end E1 or E2 thereof might be provided with thesplit-ring glands 14, armor 16, and/or sealing gasket 18. The inventionin its broader aspects is, therefore, not limited to the specificdetails, representative apparatus and method, and illustrative examplesshown and described. Accordingly, departures may be made from suchdetails without departing from the spirit or scope of the generalinventive concept.

What is claimed is:
 1. A pipe coupling for coupling two pipe endstogether, comprising: a sleeve having a generally cylindrical bodyportion with open opposing ends configured to receive the two pipe ends,the body portion extending along a longitudinal length; at least onesealing gasket operatively coupled with the sleeve for engaging at leastone of the two pipe ends; and a clamping element operatively coupledwith the sleeve for compressing the at least one sealing gasket intotightened engagement with at least one of the two pipe ends, theclamping element further including: first and second clamp membersoperatively coupled with the open opposing ends of the sleeve and the atleast one sealing gasket, the first and second clamp members includingcorresponding first and second bolt flanges nominally spaced from oneanother to define a gap therebetween, a double threaded fastening boltextending along the longitudinal length, generally parallel to the bodyportion of the sleeve and through the first and second bolt flanges ofthe first and second clamp members, the fastening bolt including firstand second external threaded portions connected at a central boltportion and respectively defining a right-hand thread and a left-handthread, and first and second fastening nuts in threaded engagement withthe first and second external threaded portions of the fastening boltand positioned to abut the respective first and second bolt flanges, thefirst fastening nut including a threaded bore with a right-hand threadand the second fastening nut including a threaded bore with a left-handthread, wherein tightening the first and second fastening nuts on thefastening bolt draws the first and second bolt flanges towards oneanother to compress the gap therebetween and thereby cause compressionof the at least one sealing gasket.
 2. The pipe coupling of claim 1,wherein the clamping element includes a plurality of double threadedfastening bolts and a plurality of corresponding sets of first andsecond fastening nuts, collectively used to tighten and loosen theclamping element relative to the sleeve.
 3. The pipe coupling of claim2, wherein the plurality of fastening bolts is equally spaced about acircumferential periphery of the sleeve and the clamping element.
 4. Thepipe coupling of claim 1, wherein the opposing ends of the sleeveinclude tapered surfaces and the at least one sealing gasket includecorresponding tapered surfaces that collectively define a wedge-shapedconfiguration at the coupling of the sleeve to the at least one sealinggasket, and wherein tightening the first and second fastening nuts onthe fastening bolt forces the at least one sealing gasket to move alongthe tapered surfaces, with the wedge-shaped configuration therebycausing inward compression of the at least one sealing gasket intotightened engagement with the at least one of the two pipe ends.
 5. Thepipe coupling of claim 4, wherein the at least one sealing gasketincludes first and second sealing gaskets each engaged with one of theopposing ends of the sleeve and one of the two pipe ends, and whereintightening the first and second fastening nuts on the fastening boltcauses simultaneous inward compression of both the first and secondsealing gaskets into tightened engagement with the two pipe ends.
 6. Thepipe coupling of claim 1, wherein the first and second fastening nutsand the fastening bolt are formed from stainless steel.
 7. The pipecoupling of claim 1, wherein the fastening bolt further comprises: aremovable head portion coupled with one of the first and second externalthreaded portions.
 8. The pipe coupling of claim 1, wherein each of thefirst and second bolt flanges includes a socket defining an arcuatesurface, and each of the first and second fastening nuts includes anarcuate surface configured to be positioned in face-to-face abuttingcontact with the arcuate surface of the corresponding first or secondbolt flange when inserted into the corresponding socket, to therebyprevent rotation of the first and second fastening nuts relative to thefirst and second bolt flanges when the first and second fastening nutsare in abutting engagement with the first and second bolt flanges. 9.The pipe coupling of claim 8, wherein each of the first and secondfastening nuts defines a convex prism shape defining the arcuate surfacewhich is to be positioned in abutting contact with the first or secondbolt flange.
 10. A method of connecting pipe ends together with a pipecoupling including a sleeve having a generally cylindrical body portionwith open opposing ends, first and second sealing gaskets, and aclamping element including first and second clamp members includingcorresponding first and second bolt flanges, a double threaded fasteningbolt, and first and second fastening nuts, the method comprising:positioning the first and second sealing gaskets adjacent the openopposing ends of the sleeve; inserting two pipe ends into the openopposing ends of the sleeve such that the first and second sealinggaskets and a portion of the sleeve surrounds the two pipe ends;engaging the first and second clamp members of the clamping element withthe open opposing ends of the sleeve and the first and second sealinggaskets such that the clamping element is operatively coupled with thesleeve, with the first and second bolt flanges nominally spaced from oneanother by a gap; inserting the fastening bolt to extend through thefirst and second bolt flanges in a direction generally parallel to thegenerally cylindrical body portion of the sleeve, with the first andsecond fastening nuts threadably engaged with first and second externalthreaded portions of the fastening bolt which define a right-hand threadand a left-hand thread, and with the first and second fastening nutspositioned to abut the first and second bolt flanges; and rotating thefastening bolt in a first direction to cause the first and secondfastening nuts to move along the corresponding first and second externalthreaded portions towards one another, thereby drawing the first andsecond bolt flanges towards one another to compress the gap and therebycause compression of the first and second sealing gaskets.
 11. Themethod of claim 10, further comprising the following steps when the twopipe ends are to be removed from the pipe coupling: rotating thefastening bolt in a second direction opposite the first direction tocause the first and second fastening nuts to move along thecorresponding first and second external threaded portions away from oneanother, thereby allowing the first and second bolt flanges to move awayfrom one another to expand the gap and release the compressiveengagement of the first and second sealing gaskets with the two pipeends; withdrawing the two pipe ends from the open opposing ends of thesleeve.
 12. The method of claim 10, wherein rotating the fastening boltresults in twice as much movement of the first and second bolt flangestowards one another for each rotation of the fastening bolt compared tofastening bolts engaged with only a single fastening nut.
 13. The methodof claim 10, wherein the clamping element includes a plurality of doublethreaded fastening bolts and a plurality of corresponding sets of firstand second fastening nuts, and the method further comprises: rotatingeach of the plurality of fastening bolts in a first direction to causethe plurality of corresponding sets of first and second fastening nutsto move towards one another, thereby drawing the first and second boltflanges of the first and second clamp members towards one another tocompress the gap and thereby cause compression of the first and secondsealing gaskets.
 14. The method of claim 10, wherein the opposing endsof the sleeve include tapered surfaces and the first and second sealinggaskets include corresponding tapered surfaces that collectively definea wedge-shaped configuration at the coupling of the sleeve to the firstand second sealing gaskets, and wherein rotating the fastening bolt inthe first direction further comprises: moving the first and second clampmembers towards one another, thereby forcing the first and secondsealing gaskets to move along the tapered surfaces, with thewedge-shaped configuration thereby causing inward compression of thefirst and second sealing gaskets into tightened engagement with the twopipe ends.
 15. The method of claim 10, wherein after inserting thefastening bolt to extend through the first and second bolt flanges, themethod further comprises: threadably engaging a removable head portionof the fastening bolt with one of the first and second external threadedportions, the removable head portion configured to engage a driver forrotating the fastening bolt.
 16. The method of claim 10, wherein each ofthe first and second bolt flanges defines a socket with an arcuatesurface, each of the first and second fastening nuts includes an arcuatesurface, the arcuate surfaces defining corresponding features configuredto prevent relative rotation, and the method further comprises: engagingthe corresponding features of the first and second bolt flanges and thefirst and second fastening nuts, by inserting the first and secondfastening nuts into the sockets of the first and second bolt flangessuch that the arcuate surfaces of the first and second fastening nutsare brought into abutting engagement with the arcuate surfaces of thefirst and second bolt flanges, to thereby prevent rotation of the firstand second fastening nuts relative to the first and second bolt flangeswhen the first and second fastening nuts are in abutting engagement withthe first and second bolt flanges.
 17. A pipe coupling for coupling twopipe ends together, comprising: a sleeve having a generally cylindricalbody portion with open opposing ends configured to receive the two pipeends, the body portion extending along a longitudinal length; at leastone sealing gasket operatively coupled with the sleeve for engaging atleast one of the two pipe ends; and a clamping element operativelycoupled with the sleeve for compressing the at least one sealing gasketinto tightened engagement with at least one of the two pipe ends, theclamping element further including: first and second clamp membersoperatively coupled with the open opposing ends of the sleeve and the atleast one sealing gasket, the first and second clamp members includingcorresponding first and second bolt flanges nominally spaced from oneanother to define a gap therebetween, the first and second bolt flangesincluding corresponding apertures, and a double threaded fastening boltextending along the longitudinal length, generally parallel to the bodyportion of the sleeve and through the apertures of the first and secondbolt flanges of the first and second clamp members, the fastening boltincluding first and second external threaded portions connected at acentral bolt portion and respectively defining a right-hand thread and aleft-hand thread, wherein rotating the fastening bolt in a firstdirection to tighten the clamping element draws the first and secondbolt flanges towards one another to compress the gap therebetween andthereby cause compression of the at least one sealing gasket.
 18. Thepipe coupling of claim 17, wherein the opposing ends of the sleeveinclude tapered surfaces and the at least one sealing gasket includecorresponding tapered surfaces that collectively define a wedge-shapedconfiguration at the coupling of the sleeve to the at least one sealinggasket, and wherein rotating the fastening bolt in the first directionforces the at least one sealing gasket to move along the taperedsurfaces, with the wedge-shaped configuration thereby causing inwardcompression of the at least one sealing gasket into tightened engagementwith the at least one of the two pipe ends, and wherein the at least onesealing gasket includes first and second sealing gaskets each engagedwith one of the opposing ends of the sleeve and one of the two pipeends, and wherein rotating the fastening bolt in the first directioncauses simultaneous inward compression of both the first and secondsealing gaskets into tightened engagement with the two pipe ends.
 19. Apipe coupling for coupling two pipe ends together, comprising: a sleevehaving a generally cylindrical body portion with open opposing endsconfigured to receive the two pipe ends; a sealing gasket operativelycoupled with the sleeve for engaging at least one of the two pipe ends;and a clamping element operatively coupled with the sleeve forcompressing the sealing gasket into tightened engagement with at leastone of the two pipe ends, the clamping element further including: firstand second bolt flanges nominally spaced from one another to define agap therebetween, a double threaded fastening bolt extending generallytangential to the generally cylindrical body portion of the sleeve andthrough the first and second bolt flanges, the fastening bolt includingfirst and second external threaded portions connected at a central boltportion and respectively defining a right-hand thread and a left-handthread, and at least one fastening nut in threaded engagement with oneof the first and second external threaded portions of the fastening boltand positioned to abut one of the first and second bolt flanges, whereinthe first and second bolt flanges include a plurality of bores alignedalong a longitudinal length of the sleeve, the plurality of boresreceiving a plurality of double threaded fastening bolts such that theclamping element is configured to compress the sleeve at multiplelocations along the longitudinal length of the sleeve, and wherein theclamping element includes an elongated split-ring cylinder includingspaced ends carrying the first and second bolt flanges so as to definethe gap between the first and second bolt flanges.